Commit 701f74fa authored by Adrian Knoth's avatar Adrian Knoth Committed by GitHub
Browse files

Merge pull request #219 from falkTX/master

Use linux futex as JackSynchro
parents 179b976f 112b6bdf
......@@ -83,10 +83,10 @@ def build(bld):
'JackDebugClient.cpp',
'timestamps.c',
'../posix/JackPosixThread.cpp',
'../posix/JackPosixSemaphore.cpp',
'../posix/JackPosixProcessSync.cpp',
'../posix/JackPosixMutex.cpp',
'../posix/JackSocket.cpp',
'../linux/JackLinuxFutex.cpp',
'../linux/JackLinuxTime.c',
]
includes = ['../linux', '../posix'] + includes
......
/*
Copyright (C) 2004-2008 Grame
Copyright (C) 2016 Filipe Coelho
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "JackLinuxFutex.h"
#include "JackTools.h"
#include "JackConstants.h"
#include "JackError.h"
#include <fcntl.h>
#include <stdio.h>
#include <sys/mman.h>
#include <syscall.h>
#include <linux/futex.h>
namespace Jack
{
void JackLinuxFutex::BuildName(const char* client_name, const char* server_name, char* res, int size)
{
char ext_client_name[SYNC_MAX_NAME_SIZE + 1];
JackTools::RewriteName(client_name, ext_client_name);
if (getenv("JACK_PROMISCUOUS_SERVER")) {
snprintf(res, size, "jack_sem.%s_%s", server_name, ext_client_name);
} else {
snprintf(res, size, "jack_sem.%d_%s_%s", JackTools::GetUID(), server_name, ext_client_name);
}
}
bool JackLinuxFutex::Signal()
{
if (!fFutex) {
jack_error("JackLinuxFutex::Signal name = %s already deallocated!!", fName);
return false;
}
if (fFlush) {
return true;
}
if (! __sync_bool_compare_and_swap(&fFutex->futex, 0, 1))
{
// already unlocked, do not wake futex
if (! fFutex->internal) return true;
}
::syscall(__NR_futex, fFutex, fFutex->internal ? FUTEX_WAKE_PRIVATE : FUTEX_WAKE, 1, NULL, NULL, 0);
return true;
}
bool JackLinuxFutex::SignalAll()
{
return Signal();
}
bool JackLinuxFutex::Wait()
{
if (!fFutex) {
jack_error("JackLinuxFutex::Wait name = %s already deallocated!!", fName);
return false;
}
if (fFutex->needsChange)
{
fFutex->needsChange = false;
fFutex->internal = !fFutex->internal;
}
for (;;)
{
if (__sync_bool_compare_and_swap(&fFutex->futex, 1, 0))
return true;
if (::syscall(__NR_futex, fFutex, fFutex->internal ? FUTEX_WAIT_PRIVATE : FUTEX_WAIT, 0, NULL, NULL, 0) != 0 && errno != EWOULDBLOCK)
return false;
}
}
bool JackLinuxFutex::TimedWait(long usec)
{
if (!fFutex) {
jack_error("JackLinuxFutex::TimedWait name = %s already deallocated!!", fName);
return false;
}
if (fFutex->needsChange)
{
fFutex->needsChange = false;
fFutex->internal = !fFutex->internal;
}
const uint secs = usec / 1000000;
const int nsecs = (usec % 1000000) * 1000;
const timespec timeout = { static_cast<time_t>(secs), nsecs };
for (;;)
{
if (__sync_bool_compare_and_swap(&fFutex->futex, 1, 0))
return true;
if (::syscall(__NR_futex, fFutex, fFutex->internal ? FUTEX_WAIT_PRIVATE : FUTEX_WAIT, 0, &timeout, NULL, 0) != 0 && errno != EWOULDBLOCK)
return false;
}
}
// Server side : publish the futex in the global namespace
bool JackLinuxFutex::Allocate(const char* name, const char* server_name, int value, bool internal)
{
BuildName(name, server_name, fName, sizeof(fName));
jack_log("JackLinuxFutex::Allocate name = %s val = %ld", fName, value);
if ((fSharedMem = shm_open(fName, O_CREAT | O_RDWR, 0777)) < 0) {
jack_error("Allocate: can't check in named futex name = %s err = %s", fName, strerror(errno));
return false;
}
ftruncate(fSharedMem, sizeof(FutexData));
if ((fFutex = (FutexData*)mmap(NULL, sizeof(FutexData), PROT_READ|PROT_WRITE, MAP_SHARED|MAP_LOCKED, fSharedMem, 0)) == NULL) {
jack_error("Allocate: can't check in named futex name = %s err = %s", fName, strerror(errno));
close(fSharedMem);
fSharedMem = -1;
shm_unlink(fName);
return false;
}
fPrivate = internal;
fFutex->futex = value;
fFutex->internal = internal;
fFutex->wasInternal = internal;
fFutex->needsChange = false;
fFutex->externalCount = 0;
return true;
}
// Client side : get the published futex from server
bool JackLinuxFutex::Connect(const char* name, const char* server_name)
{
BuildName(name, server_name, fName, sizeof(fName));
jack_log("JackLinuxFutex::Connect name = %s", fName);
// Temporary...
if (fFutex) {
jack_log("Already connected name = %s", name);
return true;
}
if ((fSharedMem = shm_open(fName, O_RDWR, 0)) < 0) {
jack_error("Connect: can't connect named futex name = %s err = %s", fName, strerror(errno));
return false;
}
if ((fFutex = (FutexData*)mmap(NULL, sizeof(FutexData), PROT_READ|PROT_WRITE, MAP_SHARED|MAP_LOCKED, fSharedMem, 0)) == NULL) {
jack_error("Connect: can't connect named futex name = %s err = %s", fName, strerror(errno));
close(fSharedMem);
fSharedMem = -1;
return false;
}
if (! fPrivate && fFutex->wasInternal)
{
const char* externalSync = getenv("JACK_INTERNAL_CLIENT_SYNC");
if (externalSync != NULL && strstr(fName, externalSync) != NULL && ++fFutex->externalCount == 1)
{
jack_error("Note: client %s running as external client temporarily", fName);
fFutex->needsChange = true;
}
}
return true;
}
bool JackLinuxFutex::ConnectInput(const char* name, const char* server_name)
{
return Connect(name, server_name);
}
bool JackLinuxFutex::ConnectOutput(const char* name, const char* server_name)
{
return Connect(name, server_name);
}
bool JackLinuxFutex::Disconnect()
{
if (!fFutex) {
return true;
}
if (! fPrivate && fFutex->wasInternal)
{
const char* externalSync = getenv("JACK_INTERNAL_CLIENT_SYNC");
if (externalSync != NULL && strstr(fName, externalSync) != NULL && --fFutex->externalCount == 0)
{
jack_error("Note: client %s now running as internal client again", fName);
fFutex->needsChange = true;
}
}
munmap(fFutex, sizeof(FutexData));
fFutex = NULL;
close(fSharedMem);
fSharedMem = -1;
return true;
}
// Server side : destroy the futex
void JackLinuxFutex::Destroy()
{
if (!fFutex) {
return;
}
munmap(fFutex, sizeof(FutexData));
fFutex = NULL;
close(fSharedMem);
fSharedMem = -1;
shm_unlink(fName);
}
} // end of namespace
/*
Copyright (C) 2004-2008 Grame
Copyright (C) 2016 Filipe Coelho
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#ifndef __JackLinuxFutex__
#define __JackLinuxFutex__
#include "JackSynchro.h"
#include "JackCompilerDeps.h"
#include <stddef.h>
namespace Jack
{
/*!
\brief Inter process synchronization using Linux futex.
Based on the JackPosixSemaphore class.
Adapted to work with linux futex to be as light as possible and also work in multiple architectures.
Adds a new 'MakePrivate' function that makes the sync happen in the local process only,
making it even faster for internal clients.
*/
class SERVER_EXPORT JackLinuxFutex : public detail::JackSynchro
{
private:
struct FutexData {
int futex; // futex, needs to be 1st member
bool internal; // current internal state
bool wasInternal; // initial internal state, only changes in allocate
bool needsChange; // change state on next wait call
int externalCount; // how many external clients have connected
};
int fSharedMem;
FutexData* fFutex;
bool fPrivate;
protected:
void BuildName(const char* name, const char* server_name, char* res, int size);
public:
JackLinuxFutex():JackSynchro(), fSharedMem(-1), fFutex(NULL), fPrivate(false)
{}
bool Signal();
bool SignalAll();
bool Wait();
bool TimedWait(long usec);
bool Allocate(const char* name, const char* server_name, int value, bool internal = false);
bool Connect(const char* name, const char* server_name);
bool ConnectInput(const char* name, const char* server_name);
bool ConnectOutput(const char* name, const char* server_name);
bool Disconnect();
void Destroy();
void MakePrivate(bool priv);
};
} // end of namespace
#endif
......@@ -54,8 +54,8 @@ namespace Jack { typedef JackPosixThread JackThread; }
namespace Jack { typedef JackFifo JackSynchro; }
*/
#include "JackPosixSemaphore.h"
namespace Jack { typedef JackPosixSemaphore JackSynchro; }
#include "JackLinuxFutex.h"
namespace Jack { typedef JackLinuxFutex JackSynchro; }
/* __JackPlatformChannelTransaction__ */
/*
......
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